排序方式： 共有10条查询结果，搜索用时 109 毫秒
1
1.
2.
SHI Dehong YIN Xi SUN Jichao YIN ZhengzhouInstitute of Hydrogeology Engineering Geology CAGS Zhengding Hebei Province Zhou Jian Zhu Xiling 《《地质学报》英文版》1998,72(1):100-107
Three Cenozoic basins-the Qaidam basin, the Weihe graben-type basin and the North China plain-which are different in climatic conditions, geological settings and run-off types, are selected for the study. Based on an analysis of background information of the transect along the middle-latitude region, studies of groundwater dynamics, geochemistry, simulation of water circulation of the main elements as well as isotopic chronology, the information on global changes is collected, the formation of groundwater circulation systems and their evolution under stacked impacts of natural conditions and human activities are discussed, and a correlation is made between the evolutionary features of the above systems in these basins since 25 ka B.P. All these have laid a good foundation for further generalizing the evolutionary model of land water in northern China. 相似文献
3.
4.
沧州市深层水中氟离子变化与地层释水估算 总被引：3，自引：0，他引：3
沧州市地面沉降过程中地层压密释水导致水资源组成发生变化,这部分释水量是水均衡计算中必须要考虑的,但现有的调查数据并不明确。通过地下水中氟离子浓度的变化来解释地面沉降与弱透水层释水机理,并采用二元混合模型估算地下水开采资源组成中越流与释水所占份额。结果显示:沧州市承压含水层中氟离子浓度与地面沉降量存在着对应关系,在压缩释水阶段,开采量中有56%来自黏性土压密释水;在越流发生阶段,开采量中有36%来自越流补给。这表明压密黏性土释水是水资源评价的重要组成部分。 相似文献
5.
YAO Hanbing HU Heping LU Zhengding LI Ruixuan 《地球空间信息科学学报》2006,9(3):223-228
IntroductionThe Grid security infrastructure ( GSI) hasbeen accepted as the pri mary authenticationmechanismfor the Grid computing. GSI devel-oped as part of the Globus project defines singlesign-on algorithms and protocols , cross-domainauthentication pr… 相似文献
6.
LU YaoruInstitute of Hydrogeology Environmental Geology Chinese Academy of GeologicalSciences Zhengding China 《《地质学报》英文版》2001,75(3):239-248
This paper discusses the rational exploitation of main resources and prevention of geohazards in karst regions. There exist relationship chains between natural disasters in the earth, which include the chain between geological hazards and climatic hazards, the chain between geological hazards and biogenic hazards as well as the one between geological hazards. Irrational exploitation of all resources will inevitably cause hazards. Therefore it is very important to discuss the problem related to prevention of geohazards by rational exploitation of resources. 相似文献
7.
ZHANG Fawang ZHANG Zhaoji HAN Zhantao SUN Jianping XIAO Guoqiang Institute of Hydrogeology Environmental Geology Chinese Academy of Geological Sciences Zhengding China Center of Hydrogeology Environmental Geology China Geology Survey Baoding China Tianjin Center of China Geology Survey Tianjin China 《《地质学报》英文版》2009,83(4)
This paper introduced the first hand investigation results of the risk and treatment measures for the barrier lakes triggered by the earthquake of Wenchuan.Characteristics of 10 barrier lakes were investigated and analyzed;procedure and methods for barrier lake treatment were brought forward.The dams of the barrier lakes can be classified as two classes:block rock in the south and loose deposit in the north.All the barrier dams were stable at the time of investigation,but water drainage channel needed to... 相似文献
8.
Grid computing is concerned with the sharing and coordinated use of diverse resources in distributed “virtual organizations”. The heterogeneous, dynamic and multi-domain nature of these environments makes challenging security issues that demand new technical approaches. Despite the recent advances in access control approaches applicable to Grid computing, there remain issues that impede the development of effective access control models for Grid applications. Among them there are the lack of context-based models for access control, and reliance on identity or capability-based access control schemes. An access control scheme that resolve these issues is presented, and a dynamically authorized role-based access control (D-RBAC) model extending the RBAC with context constraints is proposed. The D-RABC mechanisms dynamically grant permissions to users based on a set of contextual information collected from the system and user's environments, while retaining the advantages of RBAC model. The implementation architecture of D-RBAC for the Grid aplication is also described. 相似文献
9.
Yan Baorui Zhang Sheng Hu Dachun Institute of Hydrogeology Engineering Geology Chinese Academy of Geological Sciences Zhengding Hebei Liu Linqun 《《地质学报》英文版》1992,66(4)
Using the concept of the interactive water rock- microbe system of ocean floor, the microbialmineralization of ocean-floor polymetallic concretions in the central Pacific Ocean has been studied for the firsttime. Through the correlation and study of the microbial activity and formation mechanism of polymetallicconcretions, the microbial and chemical processes for. transforming mineralizing materials and the observationand determination of the concentration of mineralizing material in the system and the variation ofenvironmental parameters, this paper reveals the reaction rate and evolutionary direction of mineralizing com-ponents caused by microbial activity, expounds the microbial mineralization mechanism and formation modelof polymetallic concretions from the angle of microbial geochemical action, and suggests a threefold division ofthe microbial mineralization stages 相似文献
10.
土体微观结构的研究现况评述 总被引：7，自引：0，他引：7
本文回顾了土体微观结构的研究历史,介绍并评述了微观结构研究中各个方面的研究技术和方法,指出了微观结构研究的最新进展和发展趋势。 相似文献
1